/**
 * ***************************************************************************** Copyright (c)
 * 2012-2015 Red Hat, Inc. All rights reserved. This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * <p>Contributors: Red Hat, Inc. - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.che.ide.ext.java.jdt.text.edits;

/**
 * A visitor for text edits.
 *
 * <p>For each different concrete text edit type <it>T</it> there is a method:
 *
 * <ul>
 *   <li><code>public boolean visit(<it>T</it> node)</code> - Visits the given edit to perform some
 *       arbitrary operation. If <code>true </code> is returned, the given edit's child edits will
 *       be visited next; however, if <code>false</code> is returned, the given edit's child edits
 *       will not be visited. The default implementation provided by this class calls a generic
 *       method <code>visitNode(<it>TextEdit</it> node)</code>. Subclasses may reimplement these
 *       method as needed.
 * </ul>
 *
 * <p>In addition, there are methods for visiting text edits in the abstract, regardless of node
 * type:
 *
 * <ul>
 *   <li><code>public void preVisit(TextEdit edit)</code> - Visits the given edit to perform some
 *       arbitrary operation. This method is invoked prior to the appropriate type-specific <code>
 *       visit</code> method. The default implementation of this method does nothing. Subclasses may
 *       reimplement this method as needed.
 *       <p>
 *   <li><code>public void postVisit(TextEdit edit)</code> - Visits the given edit to perform some
 *       arbitrary operation. This method is invoked after the appropriate type-specific <code>
 *       endVisit</code> method. The default implementation of this method does nothing. Subclasses
 *       may reimplement this method as needed.
 * </ul>
 *
 * <p>For edits with children, the child nodes are visited in increasing order.
 *
 * @see TextEdit#accept(TextEditVisitor)
 */
public class TextEditVisitor {

  /**
   * Visits the given text edit prior to the type-specific visit. (before <code>visit</code>).
   *
   * <p>The default implementation does nothing. Subclasses may reimplement.
   *
   * @param edit the node to visit
   */
  public void preVisit(TextEdit edit) {
    // default implementation: do nothing
  }

  /**
   * Visits the given text edit following the type-specific visit (after <code>endVisit</code>).
   *
   * <p>The default implementation does nothing. Subclasses may reimplement.
   *
   * @param edit the node to visit
   */
  public void postVisit(TextEdit edit) {
    // default implementation: do nothing
  }

  /**
   * Visits the given text edit. This method is called by default from type-specific visits. It is
   * not called by an edit's accept method. The default implementation returns <code>true</code>.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visitNode(TextEdit edit) {
    return true;
  }

  /**
   * Visits a <code>RangeMarker</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(RangeMarker edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>CopyingRangeMarker</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(CopyingRangeMarker edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>DeleteEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(DeleteEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>InsertEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(InsertEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>ReplaceEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(ReplaceEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>UndoEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(UndoEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>MultiTextEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(MultiTextEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>MoveSourceEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(MoveSourceEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>MoveTargetEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(MoveTargetEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>CopySourceEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(CopySourceEdit edit) {
    return visitNode(edit);
  }

  /**
   * Visits a <code>CopyTargetEdit</code> instance.
   *
   * @param edit the node to visit
   * @return If <code>true</code> is returned, the given node's child nodes will be visited next;
   *     however, if <code>false</code> is returned, the given node's child nodes will not be
   *     visited.
   */
  public boolean visit(CopyTargetEdit edit) {
    return visitNode(edit);
  }
}
